Radiation-induced effects on alternative fuels

Asphaltenes obtained from high-ash coal by precipitation with n-hexane were X-ray irradiated at different doses. The gases evolved from the irradiated samples consist mainly of ethane and propane. The condensed matter obtained upon irradiation was fractionated by Preparative Liquid Chromatography (PLC) into 8 discrete fractions and its relative distribution was studied as a function of the irradiation doses. Based on the product distribution as well as the analysis of the initial sample using PLC, GPC and IV and NMR spectroscopies, a mechanism is proposed to explain the X-ray effects on the irradiation of asphaltenes.     

Radiation-induced effects on alternative fuels

Asphaltenes obtained from high-ash coal by precipitation with n-hexane were γ-ray irradiated at different doses up to 320 kGy. After irradiation the vials were opened and submitted to chemical analysis using chromatography (PLC, GPC, GC), spectroscopic (MMR IR) and additional methods (elemental analysis, VPO). Based upon the class distribution obtained through preparative liquid chromatography (PLC-8) and the chemical analysis, a mechanism is proposed to explain the γ-ray effects on the irradiation of asphaltenes.     

Radiation-induced effects on alternative fuels

Asphaltols obtained by benzene precipitation of coal-derived liquids extracted with hot pyridine were purified by preparative liquid chromatography and X-ray irradiated to different doses. The irradiated product was analyzed using chromatographic and spectroscopic methods. The results obtained show that asphaltenes are degraded to resins.     

Radiation-induced effects on electrical-grade insulating oils

Samples of a new, naphthenic based electrical-grade insulating mineral oil (type AV-58), were irradiated with -rays from a⁶⁰Co source. Doses of up to 640 kGy were used in order to investigate the chemical effects promoted by -rays in the oils. After irradiation the samples were fractionated by preparative liquid chromatography into eight compound classes, which were then analyzed by high resolution gas chromatography. By comparing the profile of each class with the equivalent fractions of the same oil without irradiation, it could be concluded that no appreciable changes were found within the dose range investigated. This result indicates that -ray irradiation of contaminants, such as PCB's, in these oils could be conducted without matrix interference.     

Problems of producing motor fuels from alternative raw materials

The mechanism and kinetics of reactions occurring in different processes of natural gas processing to motor fuels are considered. Among them are the syntheses of methanol, dimethyl ether, and gasoline from synthesis gas (syngas) and production of pure hydrogen from methanol. The general scheme of carbon-containing raw materials processing to produce motor fuels is considered using natural gas as example. The advantages of the direct synthesis of dimethyl ether (DME) from syngas (instead of methanol synthesis) over all processes producing motor fuels were shown. The synthesis of DME uses the syngas of almost any composition and, hence, the process scheme of carbon-containing feedstock syngas DME gasoline becomes universal and appropriate for processing various raw materials. Prospects of using methanol as an easily transportable source of pure hydrogen were considered. The steam reforming of methanol is a reaction inverse to its synthesis. The oxidation of residual CO in order to purify hydrogen is favored in the mode of catalyst surface ignition. Modern catalysts and methods for removal of CO traces can provide production of pure hydrogen by methanol processing with an efficiency appropriate, in principle, for using the corresponding devices aboard a vehicle.The materials of the report at the III International School Engineering Chemical Science for Advanced Technologies¹ and recent publication² were used in part.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2352–2363, November, 2004.     

Chromatographic characterization of thermally upgraded products from alternative fuels

An overview is presented of the analytical approaches developed by our research group over the last ten years for analysis of alternative fuel, both biomass and fossil. The alternative fuels are analyzed successively by PLC-8 (preparative liquid chromatography–group-type) fractionation and high resolution gas chromatography. Some of the possibilities for fractionation and characterization of alternative fuels are herein exemplified with sugar cane bagasse pyrolysis products.     

Group-type fractionation of petroleum and alternative fuels by column liquid chromatography

The present paper introduces an instrumental procedure based on column liquid chromatography for the total analysis of petroleum heavy ends and similar samples. The procedure avoids the precipitation of asphaltenes and asphaltols. One sequence of eluents fractionates the sample into 8 fractions: 5 non-polar (hydrocarbons), one intermediate (resins), and 2 polar fractions (asphaltenes and asphaltols). Quantitative results from gravimetric measurements and UV-Vis and FTIR spectra of fractions obtained from petroleum heavy ends are presented, as well as those from GC/MS data obtained from one fraction obtained from liquefaction of biomass. The method presented is easy to set up and operate, requires minimum operator attention, is reliable (no precipitation), reproducible, and inexpensive.     

Effects of novel intake manifold design and investigation of diesel engine operating on different alternative fuels

Journal of Thermal Analysis and Calorimetry - The present work focuses on performance improvement and emission reduction of conventional diesel engine's performance by incorporating various...     

Correction: Effects of novel intake manifold design and investigation of diesel engine operating on different alternative fuels

Journal of Thermal Analysis and Calorimetry -     

Bacterial acyltransferases as an alternative for lipase-catalyzed acylation for the production of oleochemicals and fuels

Bacterial acyltransferases are a new class of enzymes, and the first member was identified as WS/DGAT in Acinetobacter baylyi ADP1. Their unspecificity have been used in several biotechnological applications for lipid modification, a field that has been dominated by the use of lipases. Examples are the biosynthesis of jojoba-like wax esters and fatty-acid ethyl esters. In addition, these enzymes are also capable of synthesizing acylthioesters. Acyloxoesters and acylthioesters can thus be produced in vivo by whole-cell fermentations rather than in vitro in an enzyme reactor. In this Minireview, we focus on the biotechnological utilization of acyltransferases for the production of modified lipids from renewable resources.     

Structural effects on the reactivity of substituted arylphosphines as potential oxygen-scavenging additives for future jet fuels

Efforts to develop oxygen-scavenging additives for future jet fuels (JP-900) are presented. Results from radiolytic experiments are used to develop structure-reactivity relationships for electron-transfer-initiated oxygenation (ETIO) of variously substituted arylphosphines. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:133–138, 1998     

Radiation-induced isomerization of benzene

Summary It was shown that, when liquid benzene saturated with argon is subjected to the action of accelerated electrons, the isomeric hydrocarbon fulvene is formed. The yield of fulvene is 0.76–0.85 molecules/100 ev.Paper read at a session of the Section of Radiochemistry and Chemistry of Isotopes at the Eighth Mendeleev Congress on General and Applied Chemistry.     

Radiation-induced dechlorination of hexachlorobenzene

A study on radiation-induced dechlorination of hexachlorobenzene in alkaline ethanol solution was performed. At the beginning a higher efficiency for dechlorination has been found. The dechlorination is a chain reaction. The solubility of radiolytic products in ethanol-water (v/v 1:4) is higher than that of HCB in the same solvent. Hexachlorobenzene could be transfered into the solution and degraded partially if the soil contaminated by hexachlorobenzene was mixed with ethanol, then irradiated with γ-rays.     

Radiation-induced postpolymerization of nitroethylene

Radiation-induced postpolymerization of nitroethylene in 2-methyltetrahydrofuran glass has been studied and discussed in reference to the results obtained from ESR measurements. No postpolymerization occurred at the temperature below ?150°C. In the temperature range between ?135°C and ?78°C, the polymer yield decreased with increasing postpolymerization temperature. The polymer yield increased linearly with the increase of the preirradiation dose in the range below 0.9 × 10⁶ r. The mean value for chain initiation was estimated to be about 1.3. The following correlations were observed between the results of the postpolymerization and ESR measurements. The postpolymerization started in the temperature range between ?140°C and ?135°C, where the ESR spectrum due to the anion radicals of nitroethylene disappeared. The polymer yield of the postpolymerization decreased with the photoirradiation at ?196°C before warming the samples in parallel with the photobleachability of the anion radicals observed in the glassy mixture by the ESR method. It was concluded from these results that the radiation-induced postpolymerization was initiated by the anion radicals of nitroethylene formed by the capture of electons.     

TG and autoignition studies on forest fuels

The autoignition delay times of some important Mediterranean forest species: Arbutus adrachne, Abies cephallonica, Pinus brutia, Pinus halepensis, Pistacia lentiscus, Cupressus semprevirens, Olea europaea, Cistus incanus were determined in the range 460–600°C under precisely controlled temperature and airflow conditions. Based on these data the forest fuels examined were classified into two groups: the least and the most flammable species. The autoignition delay data were related to the thermal analysis measurements. The themogravimetric analysis in an inert (nitrogen) atmosphere showed that the thermal decomposition of cellulose in the range of 300–400°C as well as the mass residue at 600°C are directly related to the ignition behavior.This revised version was published online in November 2005 with corrections to the Cover Date.     

Studies on the dissolution of carbide fuels

The dissolution of carbide fuels was tried with the aid of various oxidants like H₂O₂, NaBiO₃, (NH₄)₂Ce(NO₃)₆, (NH₄)₂S₂O₈, and AgO in nitric acid medium. During the dissolution, the carbon dioxide liberated has been measured. Among the oxidants studied, H₂O₂ and NaBiO₃ appeared to be more effective for dissolution of carbides. 200–300 mg of sintered uranium carbide sample dissolved within 15 minutes in the presence of oxidants H₂O₂ or NaBiO₃. Mixed carbide sample (70%) was dissolved within 30 min, whereas plutonium carbide required more than one hour. From the resulting solutions uranium and plutonium could be determined by conventional redox methods. More than 97% of plutonium could be recovered and purified from the resulting carbide solutions by conventionally used anion exchange method.     

The first-principles treatment of the electron-correlation and spin-orbital effects in uranium mononitride nuclear fuels

The DFT+U calculations were employed in a detailed study of the strong electron correlation effects in a promising nuclear fuel-uranium mononitride (UN). A simple method for solving the multiple minima problem in DFT+U simulations and insure obtaining the correct ground state is suggested and applied. The crucial role of spin-orbit interactions in reproduction of the U atom total magnetic moment is demonstrated. Basic material properties (the lattice constants, the spin- and total magnetic moments on U atoms, the magnetic ordering, and the density of states) were calculated varying the Hubbard U-parameter. By varying the tetragonal unit cell distortion, the meta-stable states have been carefully identified and analyzed. The difference in the magnetic and structural properties obtained for the meta-stable and ground states is discussed. The optimal effective Hubbard parameter U(eff) = 1.85 eV reproduces correctly the UN anti-ferromagnetic ordering, and only slightly overestimates the experimental total magnetic moment of the U atom and the unit cell volume.     

Radiation-induced polymerization of 1,1,2-trichlorobutadiene

The γ-ray-induced polymerization of 1,1,2-trichlorobutadiene, m.p. ?48.5°C., was investigated in the temperature range from +55 to ?196°C. In the liquid state, the following results were obtained: (1) the rate decreases with decrease of temperature (E_a = 8.0 kcal./mole); (2) the dose rate dependences of rate and of molecular weight are 0.49 and ?0.25, respectively; (3) the reaction is inhibited by DPPH; (4) the structure of the polymer is predominantly 1,4 units. It was concluded that the liquid-state polymerization proceeds by a radical mechanism, and the radical yield was found to be 19.7. In the solid state, the following results were obtained: (1) the rate is considerably higher than in the liquid state immediately above the melting point and gradually decreases with decrease of temperature (E_a = 0.34 kcal./mole); (2) the dependence of the rate on dose rate is unity while the molecular weight is independent of the dose rate; (3) the reaction rate is unaffected by DPPH and accelerated by dimethylformamide; (4) the structure of the polymer, 3,4 units, is completely different from that of the polymer obtained in the liquid-state polymerization. The solid-state polymerization is probably of a different nature and is not well elucidated.     

Radiation-induced bulk polymerization of maleimide

Radiation-induced bulk polymerization of maleimide in both solid and liquid states was studied. Benzoquinone inhibited the liquid-state polymerization and retarded solid-state polymerization. The results of ESR study showed that solid monomer irradiated at 61°C. gave a spectrum, the concentration of which slowly decreased without changing the shape at 61°C. The radical detected at 61°C. was shown not to be the main propagating species. Overall rate polymerizations in the liquid and solid states were expressed, respectively, by first-order and zero-order rate equations with respect to the concentration of monomer. The overall rate constants in liquid and solid states were proportional to I^0.9 and I^1.0, respectively.     

Radiation-induced changes in carboxymethylated chitosan

This study focuses on the radiation effect of γ-ray on carboxymethylated chitosan (CM-chitosan) in solid state. The changes in molecular weight of CM-chitosan with absorbed dose were monitored by viscosity method. Experimental results indicated that random chain scissions took place under irradiation. Radiation chemical yield (G_d) of CM-chitosan in solid state with N₂-saturated was 0.49, which showed CM-chitosan has high radiation stability. Biomaterials composed of CM-chitosan can be thought to sterilize with low absorbed dose. FTIR and UV spectra showed that main chain structures of CM-chitosan were retained, carbonyl/carboxyl groups were formed and partial amino groups were eliminated in high absorbed dose. XRD patterns identified that the degradation of CM-chitosan occurred mostly in amorphous region.