Increases in the atmospheric levels of carbon dioxide and methane are the main causes of global warming, so measures to reduce the emissions of both gases are essential. A process converting carbon dioxide and methane into methanol was investigated combining three systems as follows, photolysis of water with solar energy, conversion of carbon dioxide and hydrogen into methane, and conversion of methane into methanol. Photolysis of water with solar energy and conversion of methane into methanol with methanotroph are described. Two different systems were attempted to achieve the photoinduced cleavage of water: photoinduced hydrogen evolution combined with Photosystem I and hydrogenase, and the combination of oxygen evolution and photoinduced hydrogen evolution systems. The oxygen evolution system contains grana and an electron carrier such as NAD and NADP. Photoinduced hydrogen evolution systems contain an electron donor, a photosensitizer, an electron carrier and a catalyst such as hydrogenase. Methane was converted into methanol by methane-oxidizing bacteria, methanotrophs which utilize methane monooxygenase to catalyze hydroxylation of methane to methanol. Using methanotrophs for methanol production, accumulation of methanol was not detected, because the methanol is subsequently oxidized by methanol dehydrogenase. The cell suspension of methanotrophs was treated by cyclopropanol as a selective inhibitor of methanol dehydrogenase, leading to extracellular methanol accumulation. The conditions of methane hydroxylation were optimized and semicontinuous methanol synthesis was achieved.
Bioethanol has become an important product recently. Manufacture depends on sugar or starch, but such processes conflict with the requirements for food supply. Lignocellulose has high potential as feedstock for bioethanol, and has been the focus of much research and development. Sulfuric acid is generally used for saccharification or pretreatment of lignocellulose, but we have developed a saccharification process not requiring sulfuric acid, which is more environment friendly, combining mechanochemical pretreatment and enzymatic saccharification processes. We studied the process design, and presented the technical and economical portfolio. Based on this portfolio, we developed low energy mechanochemical treatment and low cost saccharification processes. The commercialization of our system is expected to begin soon.
Carbocation species are considered to be important intermediates in the reactions of hydrocarbons over zeolites, and the formation mechanism, as well as the reactivity, has been studied mainly by NMR and IR spectroscopy. The present state of knowledge obtained from these studies is summarized, and experimental details of IR methods for the investigation of solid catalysis are described. As an example of IR research on the catalysis of zeolites, recent results on the formation of alkenyl cation species by the reaction of cyclic alkenes with the acidic hydroxyl groups on zeolites are summarized. The formation of alkenyl cation species was observed by adsorption of cycloalkenes on silica-alumina, HY zeolite, mordenite, H-ZSM-5 and H-beta zeolite, and characterized by IR peaks at 1490-1530 cm−1 and UV-visible peaks at 290-330 nm. Formation of alkoxyl groups in addition to alkenyl cations was observed on H-ZSM-5 with smaller pores and H-beta with weaker acidity zeolites in comparison with HY zeolite.
Application of in-situ combustion is not widespread for a variety of reasons including the relatively large expense required to evaluate prospects. Moreover, because of the complexity of in-situ combustion processes, their design must be preceded by extensive laboratory investigations to ascertain the burning characteristics of the crude, fuel availability and air requirements. The complexity of the processes has also hindered the development of accurate numerical simulators for performance prediction. In this study KEM reservoir in southwest of Iran was selected as an extra heavy carbonate reservoir. In this work, the potential of auto ignition of heavy oil during in-situ combustion process was studied in KEM reservoir. Also it was aimed to predict experimental work with simulation by implementing valid input data and to investigate the risk of carbonate decomposition due to high temperature. Thermogravimetry and Differential Thermogravimetry Analysis (TG/DTG) were used to study the kinetics of chemical reaction and determine basic kinetic constants such as the rate constant, activation energy, and frequency factor. TGA test was demonstrated that the carbonate rock decomposition was taken at 650°C. Results showed that the peak of low temperature combustion (LTC) by producing CO was initiated at 275°C when air was injected. Also, enriching the injected air by oxygen lowers the LTC by up to 50°C. Enthalpy of each reaction was obtained by Differential Scanning Calorimetry (DSC). Thus, the values of the Arrhenius kinetics parameters provided the required kinetics data for the numerical simulation the process for the reservoir. Additionally, combustion tube tests were done using KEM oil and crushed carbonate rock. In forward combustion test, auto ignition has been investigated by the application of enriched air. The forward test was followed by numerical simulation to model the tube. The results of the in-situ combustion tube test were predicted by using a commercial simulator.
Chalcones are the starting materials for the biosynthesis of flavonoids. Flavonoids are strong antioxidants, which contain many phenolic hydroxyl group(s). However, the antioxidant activities of chalcones have been little studied. In this study, chalcones with chemical structures resembling natural chalcones were synthesized, and the effects of the hydroxyl group(s) on the A and B rings and the C3 chain connecting the A and B rings were investigated in detail. Hydroxyl group(s) on the B ring inherited the characteristics of p-coumaric acid as a precursor of chalcone, if the groups were located on 2- and/or 4-positions to the C3 chain, and showed strong antioxidant activities. The 2'-hydroxy group of the A ring cooperated with the carbonyl group on the 1'-position to provide ultraviolet rays absorbing (photo-antioxidant) activity. The carbon-carbon double bond in the C3 chain, connecting the A ring with the B ring in a conjugated system, enhanced both anti?oxidant and photo-antioxidant activities. The obtained information was used in the molecular design of new polymer additives.
In this study, a new upgrading method with supercritical water was developed for heavy oil in order to produce light oil that was free from heavy metal and heavy hydrocarbon fraction under coke suppression condition. Heating experiments of the heavy oil with and without supercritical water were conducted to gain insights into temporal variation of gas, maltene, asphaltene, and coke yield and existence state of heavy metal vanadium in the heavy oil. The experiments were carried out by an autoclave apparatus with and without continuous supply of supercritical water at 25 MPa and from 400 to 470°C. Results of the experiments showed that gas and reformed oil that composed of maltene was selectively extracted by supercritical water and its extraction rate was increased proportional to temperature. It was valid for suppressing coke formation to heat the heavy oil within coke induction period. The vanadium should be enriched into heavy fraction, because concentration of vanadium in residual oil was proportional to asphaltene concentration. Based on these experimental results, a new upgrading method that works out without detriment to extraction rate of gas and reformed oil under coke suppressing condition was designed. This method was followed by heating the heavy oil at 450°C within coke induction period and extraction of gas and reformed oil at 400°C by supercritical water. We have confirmed that this upgrading method enabled us to depress the coke yield 1/70 fewer than 450°C on extraction rate at 450°C.
A series of bimetallic Pd-Pt (mole ratio Pd:Pt=4:1) catalysts supported on ultrastable Y (USY) zeolites and delaminated USY zeolites were prepared and characterized by XRD, 27Al MAS NMR and CO adsorption. The extraframework aluminum (EFAL) contributed to the increases in acidity of USY zeolites and in sulfur tolerance of Pd-Pt particles.