Production of Sustainable Aviation Fuel by Hydrocracking of n-Heptadecane Using Pt-Supported Y-Zeolite-Al2O3 Composite Catalysts.

Hydrocracking of fat or Fischer-Tropsch (FT) wax from biomass to produce the jet fuel of sustainable aviation fuel has been one of the key reactions. n-Heptadecane, which is one of the model diesel fractions produced from fat or FT wax, has hardly been used for hydrocracking of hydrocarbon for jet fuel production, while n-hexadecane has often been used as one of the model compounds for this reaction. In the present study, a HY-zeolite (50 wt %, SiO2/Al2O3 = 100)-Al2O3 (50 wt %) composite-supported Pt (0.5 wt %) catalyst [0.5Pt/Y(100)35A] was tested for hydrocracking of n-heptadecane using a fixed-bed flow reactor at a H2 pressure of 0.5 MPa, H2 flow rate of 300 mL/min, WHSV of 2.3 h-1, and a catalyst weight of 2 g. Fine-tuning of the temperature to 295 °C achieved the highest selectivity of 74% for the jet fuel fraction C8-C15 with the high conversion of 99%. The jet fuel yield reached 73%, which was almost an ideal maximum yield of 75%. Similar hydrocracking of n-hexadecane has just reported the maximum yield of 51% for jet fuel fraction. Further, 0.5Pt/Z(110)35A, which has a composition similar to that of 0.5Pt/Y(100)35A except for the type of zeolite, could not give as high yield of jet fuel as 0.5Pt/Y(100)35A because the rapid conversion to lighter fractions than the jet fuel occurred by the slight increase in the reaction temperature even at a lower temperature range.

pH response and mechanical properties of Fe2O3-TeO2-based glass/stainless steel enamel electrodes for pH sensors.

Glass pH sensors are unsuitable for in vivo biomedical, clinical, or food applications because of the brittleness of glass and the difficulty in measuring small volumes. Enamel structures such as glass/stainless steel are candidates for glass-based pH electrodes. In this study, new enamel electrodes for pH sensors using Fe2O3-TeO2-based glass/stainless steel were developed. The effect of NiO addition to Fe2O3-TeO2 glass on the pH sensitivity and the three-point bending strength of enamels were investigated. The effect of NiO addition to Fe2O3-TeO2 glass/stainless steel on the pH sensitivity was negligible. Fe2O3-TeO2-based glass/stainless steel showed pH sensitivity appropriate to a working electrode. Enameling at a lower temperature under an air atmosphere was desirable for narrowing the gap between pH 4-7 and pH 7-9 sensitivities. The NiO addition to Fe2O3-TeO2 glass/stainless steel decreased the three-point bending strength. Therefore, NiO did not serve as an adhesion oxide in the Fe2O3-TeO2 glass. Fe2O3-TeO2 glass/stainless steel possessed the highest three-point bending strength among all samples when prepared at 670 °C under an air atmosphere. Therefore, no NiO addition and enameling at a lower temperature under an air atmosphere are desirable for obtaining more robust Fe2O3-TeO2 glass/stainless steel than Li2O-SiO2-based glass electrodes for pH sensors.

Effects of Zn Addition into ZSM-5 Zeolite on Dehydrocyclization-Cracking of Soybean Oil Using Hierarchical Zeolite-Al2O3 Composite-Supported Pt/NiMo Sulfided Catalysts.

Zn-exchanged ZSM-5-Al2O3 (ZA) composite-supported Pt/NiMo (NM) sulfided catalysts were prepared using the conventional kneading method and were tested for dehydrocyclization-cracking of soybean oil. The effects of Zn addition on the activity and selectivity of products were investigated under moderate-pressure conditions of 0.5 and 1.0 MPa H2 in the temperature range of 420-580 °C. At the temperature 500 °C and higher, most of the sample soybean oil was converted at both the pressures of 0.5 and 1.0 MPa. At 1.0 MPa and 500 °C, the effects of Zn addition appeared and increased the yields of aromatics, while the catalyst without Zn produced larger amounts of products with more than C18. Further, at 0.5 MPa and 580 °C, the gas formation was inhibited in comparison to the cases of 1.0 MPa and the effects of the Zn addition also appeared and increased the yields of aromatics, while the catalyst without Zn produced larger amounts of products with more than C18. The Pt/NM/Zn(122)ZA test catalyst produced more than 63% of liquid fuels in the range C5-C18, and the yield of aromatics was 13%, the maximum value in the present study. The following reaction routes were proposed. The structure of triglyceride is converted by hydrocracking to three molecules of aliphatic acids and propane on the surface PtNiMo sulfide on Al2O3 support. The converted aliphatic acids are decomposed through decarboxylation to hydrocarbon fragments, which are further decomposed by cracking on the acid sites of the catalyst, the surface of NiMo sulfide, Al2O3, or ZSM-5. Finally, the formed C3 and C4 olefins are transformed to aromatics through the Diels-Alder reaction on the Zn species of ZnZSM-5. On the other hand, although gases were relatively small in amount, aromatic compounds were formed significantly, suggesting that cyclization might directly occur without conversion to gaseous hydrocarbons to some extent.

Analysis of Thermal Behavior of Crystalline Minerals in Bituminous Coal Samples under Air and Argon Atmospheres.

The thermal behavior of ash components in two bituminous coal samples [Upper Freeport (the "UF") and Illinois #6 (the "IL")] was investigated under air and argon atmospheres in the temperature range of 800-1200 °C using thermal gravimetric-differential thermal analysis, X-ray diffraction transmission electron microscopy (TEM), and TEM-energy dispersive X-ray spectrometry measurements. The UF treated under air formed the needle-like crystals which were assumed to be mullite-related substances formed by transformation of andalusite, because the crystals are mainly composed of SiO2 and Al2O3. In contrast to the UF, the IL did not generate such crystals; however, when the IL was treated under air after carbonization under Ar, crystals appeared. The composition of the UF with an Al/Si ratio higher than that of the IL favored the formation of mullite-related substances, while the presence of lime in the IL inhibited the formation of mullite-related substances. Oldhamite was formed by the reaction of lime with sulfur at the carbonization of the IL under Ar and remained even at the successive air treatment. As lime was consumed, the formation of mullite-related substances was ceased to be inhibited under air after Ar treatment.

Effects of the addition of CeO2 on the steam reforming of ethanol using novel carbon-Al2O3 and carbon-ZrO2 composite-supported Co catalysts.

Novel carbon-Al2O3 and carbon-ZrO2 composite-supported Co catalysts were prepared using the sol-gel method with polyethylene glycol (PEG) as a carbon source, and the effects of the addition of CeO2 to catalysts on the steam reforming of ethanol were investigated. The reactions were carried out in a fixed bed reactor with H2O/EtOH = 12 (mol/mol) and a temperature range of 300 °C to 600 °C. The catalyst characterization was performed by XRD, nitrogen adsorption and desorption isotherms, TG-DTA, XRF and TEM. Although the carbon-Al2O3 composite-supported Co catalysts exhibited a higher conversion of ethanol than the carbon-ZrO2 composite-supported Co catalysts, the effect of the addition of CeO2 was hardly observed for catalysts with Al2O3. In contrast to the case of catalysts with Al2O3, the effect of the addition of CeO2 to catalysts with ZrO2 on the conversion and the hydrogen yield was observed, and the hydrogen yield at 600 °C exceeded that of catalysts with Al2O3. 16Co42C31.5Ce10.5Zr exhibited the highest hydrogen yield of 89% at 600 °C. Fine Co metal species were observed for the used ZrO2-based catalysts, while Co3O4 peaks were observed for the used Al2O3-based catalysts. The development of the carbon nanotube-like structure with a diameter of 50 nm was observed with particles having diameters of 30 nm to 50 nm, suggesting that the carbon deposition might occur so as not to deactivate the catalyst.

Dehydrocyclization-cracking of methyl oleate by Pt catalysts supported on a ZnZSM-5-Al2O3 hierarchical composite.

The dehydrocyclization-cracking of methyl oleate was performed by ZnZSM-5-Al2O3 hierarchical composite-supported Pt catalysts in the range of 450-550 °C under 0.5 MPa hydrogen pressure. Most catalysts converted methyl oleate completely and produced aromatics with more than 10 wt% yield as well as valuable fuels even at 450 °C. The reactivity of catalysts changed remarkably depending on the addition method of Pt, while supporting Pt of 0-0.16 wt% did not affect the pore structure of each catalyst. When Pt was introduced into the composite support by the conventional impregnation method, remarkable hydrocracking proceeded through the decarboxylation and decarbonylation of methyl oleate and the successive conversion of C17 fragments and gave the significant amounts of gaseous products. Nevertheless, the selectivity for the aromatics of the gasoline fraction was relatively high and the yields of aromatics reached maximum 19% at 500 °C under 0.5 MPa, suggesting that gaseous olefins would be cyclized through the Diels-Alder reaction on ZnZSM-5 in the composite support. In contrast, when Pt was introduced into catalysts by ion-exchange with ZnZSM-5, the significant conversion of methyl oleate was inhibited and produced liquid fuels in a wide range.

Effects of a Matrix on Formation of Aromatic Compounds by Dehydrocyclization of n-Pentane Using ZnZSM-5-Al2O3 Composite Catalysts.

In this study, the effects of the combination of a mesoporous material and Zn-exchanged ZSM-5 on the activity and selectivity of aromatic compounds in dehydrocyclization of n-pentane were investigated. A total of 65-85 wt % of ZnZSM-5 was mixed with 0-20 wt % of Al2O3 and 15 wt % of the alumina-sol binder using a conventional kneading method. Dehydrocyclization of n-pentane was performed using a fixed-bed reactor under the conditions of a H2 atmosphere and the temperature range of 450-550 °C. Conversions of n-pentane tended to increase upon increasing the amounts of zeolite content and ZnZSM/0A (85 wt % ZnZSM-5, 0 wt % Al2O3, and 15 wt % binder) exhibited the highest value. The selectivity for toluene and benzene increased with increasing temperature, while it decreased in the order ZnZSM/10A > ZnZSM/0A > ZnZSM/20A in comparison at the same temperature. Upon changing the carrier gas, the conversion decreased in the order CH4 > H2 > H2 + N2 > N2. Although the selectivity for aromatics was higher under CH4 and N2 atmospheres, the conversions decreased at 550 °C with time, suggesting that the deactivation would proceed by coke formation. Furthermore, the selectivity for aromatics of ZnZSM/10A was higher than that of ZnZSM/0A, indicating that the use of mesoporous Al2O3 as a matrix would be very effective for this reaction and draw the maximum catalytic functions. When the reaction route was estimated from the amounts of methane and C2 and C3 fractions formed, it was proposed that active Zn species would catalyze the aromatization of olefins where benzene is formed from ethene and butene, toluene from propene and butene, and xylene from 2 molecules of butene.

Effect of heat-treatment on the pH sensitivity of stainless-steel electrodes as pH sensors.

Effect of heat-treatment on the pH sensitivity of uncoated stainless-steel electrodes was investigated to comprehend the pH sensitivity of metal-oxide coated stainless-steel electrodes as novel pH sensors. The pH sensitivity of stainless-steel electrodes as-received and heat-treated at 500 °C, 600 °C and 700 °C for 24 h were 91 %, 94 %, 102 % and 91 %, respectively. The pH sensitivity tended to increase with increasing heat-treatment time at a given temperature. Thus, the most suitable heat-treatment condition for the stainless-steel electrodes was 600 °C for 24 h. The austenite phase (fcc) was the main phase on the surface of the heat-treated stainless-steel electrodes. Unexpectedly, the change in the martensite phase (bcc) as the second phase with heat-treatment temperature was similar to the pH sensitivity, with the martensite phase affecting the pH sensitivity. Therefore, it appeared that the pH sensitivity of the metal-oxide coated stainless-steel electrodes was affected by the underlying stainless-steel as well as the outer metal-oxide film coating. A prototype stainless-steel tube electrode was used as a working electrode for demonstrating the depth profiling of pH. The stainless-steel tube electrode showed good performance for measuring pH depth profiles compared to commercially available glass electrodes.

Drastic Dependence of the pH Sensitivity of Fe2O3-Bi2O3-B2O3 Hydrophobic Glasses with Composition.

Fe2O3-Bi2O3-B2O3 (FeBiB) glasses were developed as novel pH responsive hydrophobic glasses. The influence of the glass composition on the pH sensitivity of FeBiB glasses was investigated. The pH sensitivity drastically decreased with decreasing B2O3 content. A moderate amount of Fe2O3 and a small amount of B2O3 respectively produces bulk electronic conduction and a pH response on glass surfaces. Because the remaining components of the glass can be selected freely, this discovery could prove very useful in developing novel pH glass electrodes that are self-cleaning and resist fouling.

Allergen rush immunotherapy increases interleukin (IL)-12 production and IL-12 receptor beta2 chain expression in patients with allergic asthma.

Interleukin (IL)-12 production and IL-12 receptor (IL-12R) beta2 chain expression were investigated in patients with allergic asthma successfully treated with rush immunotherapy (RIT) and control patients with mild allergic asthma. Peripheral blood mononuclear cells (PBMCs) were stimulated with Dermatophagoides farinae (Der f), and production of cytokines was measured. Furthermore, the effects of cytokines on IL-12R beta2 chain expression on CD4(+) T cells were investigated. Production by PBMCs of IL-12 and IFN-gamma was significantly higher and production of IL-4 was significantly lower after stimulation with Der f allergen in RIT-treated patients than in control patients. Significant increases in the expression of IL-12R beta2 chain before and after stimulation of CD4(+) T cells with IL-12 or IFN-gamma were observed in RIT-treated patients compared with that in control patients. Allergen RIT increases IL-12 production and IL-12R beta2 chain expression and thus may convert cytokine production from Th2 to Th1 or Th0 type in allergic asthma.

[Japanese cedar pollinosis is a risk factor for bronchial asthma in Japanese adult asthmatics].

It is well known that allergic rhinitis and asthma often coexist in the same patients. Here, we investigated the influence of Japanese cedar pollinosis on the exacerbation of asthma investigated by questionnaire, daily asthma diary, and peak expiratory flow (PEF) monitoring. Furthermore, airway responsiveness to histamine before pollen season was also investigated in some patients. 333 adult patients with asthma were enrolled into the study and 116 patients (34.8%) were suffering from Japanese cedar pollinosis diagnosed by the presence of nasal allergic symptoms during pollen season and high titer of Japanese cedar-specific IgE antibody. Exacerbation of asthma symptoms, including wheezing, dyspnea, cough, and sputum, was detected in 41 of 116 patients (35.3%) during pollen season. Decrease in morning PEF more than 10% compared with the baseline values before pollen season was observed in 13 of 41 patients (11.2% of total asthmatic patients who complicated with Japanese cedar pollinosis). No significant differences in airway responsiveness to histamine and the titer of Japanese cedar-specific IgE antibodies before pollen season were observed between the patients whose asthma exacerbated and the patients whose asthma was not exacerbated. These results suggest that Japanese cedar pollinosis is one of risk factors for asthma in Japanese adult patients with asthma.