The liquid phase oxidation of a series of neopentyl esters, chosen to model the more complex polyol esters used as lubricants, has been studied in two ways. In one, detailed product analyses, following reaction with oxygen in a closed reactor at elevated temperatures, allows for mechanisms to be proposed. In the second, the esters were reacted with two different alkoxyl radicals, the results leading to valuable information about the relative rates of attack on the various C-H bonds. For example, it was found that attack could take place readily on both the alkyl and acyl groups in the ester and that the β-acyl C-H bonds are more susceptible to attack than α-C-H bonds.
To support the proposals for the mechanisms, details are given of experiments in which reactions of specific peroxyl radicals derived from esters were studied in detail and compared with similar experiments with alkylperoxyl radicals. The reactions of peroxyl radicals formed from esters are similar to those derived from alkanes and it is possible to use rate constants for reactions of alkylperoxyl and related oxygenated radicals to model successfully the reactions of the esterperoxyl radicals.
Overall the mechanisms for the autoxidation of the esters can be explained in terms of well-established mechanisms associated with the autoxidation of alkanes, as would be expected from the similarity of the peroxyl radical chemistry of the two systems. However, care has to be taken in accounting for the influence of the functional group which has a profound effect on the point of attack in the case of the autoxidation of the esters.

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Molybdovanadophosphoric acids (HPMoV) and their salts (NPMoV) partly substituted with an ammonium cation are efficient reoxidation systems for the Pd(OAc)₂-catalyzed oxidation of alkenes and arenes with molecular oxygen. Acetoxylation of various cycloalkenes to 3-acetoxy-1-cycloalkenes was performed in good yields by the Pd(OAc)₂/NPMoV/O₂ system combined with hydroquinone. Oxidation of cyclohexene and styrene to the corresponding ketones by the same catalytic system in a mixed solvent of ethanol and water formed cyclohexanone and acetophenone, respectively, in fair to good yields. Monosubstituted alkenes such as ethyl acrylate and acrylonitrile underwent acetalization by this catalytic system to give the corresponding acetals in quantitative yields. Wacker-type oxidation of long-chain terminal alkenes by the present catalytic system was successfully achieved in the presence of a small amount of chloride ion. For example, oxidation of 1-octene formed 2-octanone (83%) as the major product, and the formation of undesired 3-octanone was less than 1%. The regioselectivity and yield of ketones were improved by dropwise addition of alkenes to the reaction system. The Pd(OAc)₂/NPMoV/O₂ system also acts as a good oxidation system for the carbomethoxylation of alkenes. Cyclopentene was carbomethoxylated under a mixture of CO (0.5 MPa) and air (0.5 MPa) to give dimethyl cis-1, 2- and cis-1, 3-cyclopentanedicarboxylates in good yields. Oxidative coupling reaction of benzene to biphenyl was performed by Pd(OAc)₂ combined with HPMoV under dioxygen at 90°C. The best turn-over number of Pd(OAc)₂ reached 109 and the yield of biphenyl was 14.3% based on the benzene used.

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Any given method for the analysis of semi-volatile total petroleum hydrocarbons (TPH, C₁₀-C₃₆) in contaminated soil is made up of a number of procedures, each of which may be subject to improvement or optimization. One such procedure involves the extraction of TPH from soil samples using an appropriate solvent. A solvent that is widely used is dichloromethane (DCM). Ideally, the chosen solvent should represent the best compromise between factors such as cost, extraction efficiency and occupational health and safety concerns. We have initiated a search for alternatives to neat DCM which are equally efficient at solubilising TPH over a range of soil types, but which are less expensive to purchase and dispose of, and which are less toxic. Two studies were carried out involving the analysis of TPH levels in a total of 78 field samples, from a number of contaminated sites. For Study 1, TPH levels were determined for 36 samples (from five different sites), comparing the use of neat DCM versus 50%v/v DCM/acetone as extractant solvents. For Study 2, TPH levels were determined for 42 samples (from one site), comparing the use of 50%v/v DCM/acetone versus neat 2-propanol as extractant solvents. Apart from varying the extractant solvent, all other aspects of the method were kept constant. The soils were characterized for all samples, and the six sites were found to have similar moisture content and soil type distributions. Levels of TPH in the extracts were determined by gas chromatography with flame ionization detection (GC/FID) and, using the paired t-test, were statistically compared between each of the two pairs of extractant solvents used. These investigations suggest that for routine field samples, and for sites of the type represented here, 50%v/v DCM/acetone may be confidently substituted for neat DCM as an extractant solvent. However, 2-propanol is not recommended as a substitute for either 50% DCM/acetone or DCM.

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Synthesis of di-t-butyl-polysulfide from isobutene, hydrogen sulfide and sulfur was carried out over solid base catalysts such as alkali metal and alkaline earth metal oxides loaded on alumina. The performance of the solid base catalysts was compared with that of dicyclohexylamine(liquid catalyst). Alkali metal and alkaline earth metal oxide catalysts were prepared by loading the metal oxide on γ-Al₂O₃ by the impregnation or ion exchange methods. The reactions were carried out at 120-135°C and 0.3-3 MPa with an autoclave and a semi-batch reaction system in which the mixed gas of isobutene and hydrogen sulfide was bubbled through molten sulfur and the catalyst packed in the autoclave. Liquid products were analyzed with mass spectrometry, X-ray fluorescence spectrometry, HPLC, FT-IR, ¹H-NMR and ¹³C-NMR. The results showed that di-t-butyl-polysulfide was formed in the reactions over all catalysts. The number of bridging sulfurs in the polysulfide was 3 to 9, and an average number of sulfur bridges was 4.5 to 5.5. The distribution of bridging sulfurs in the polysulfide formed over solid base catalyst was almost the same as that for the polysulfide formed over the liquid amine catalyst. Polysulfide yield increased with higher metal loading up to about 0.5 mmol/g-Al₂O₃ for alkali metal catalysts, and up to about 0.3 mmol/g-Al₂O₃ for alkaline earth metal catalysts. Further increases in metal loading up to about 1.5 mmol/g-Al₂O₃ had little effect on the polysulfide yield. The addition of polysulfide to the reaction system considerably increased the reaction rate. The promotion effect was probably due to an increase in solubility of the gaseous reactants in the miscible phase of molten sulfur and polysulfide.

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Hydrodesulfurization (HDS) of atmospheric residue (AR) carried out over Ni-Mo or Co-Mo catalyst requires a sudden increase in the reaction temperature for the desired desulfurization at the end of operation (EOR). This phenomenon is mainly caused by reduced diffusion rate due to metal deposition in the pore mouth. The present study performed HDS over catalysts with different pore size to separately examine the effects of metal and coke deposition on catalyst deactivation. HDS catalysts used in a commercial process for 1 year were analyzed by EPMA to determine the coke and metal distribution along the catalyst radius. A model equation was developed to quantitatively estimate the coke and metal distribution. The model equation could estimate parameters such as Thiele modulus and catalyst properties coefficient. Furthermore, the equation was applicable to used catalyst obtained from commercial equipment and to used catalysts with different pore radii after HDS of Boscan crude containing large amounts of metals and asphaltenes. The distributions of coke and metals could be simulated with the model equation, giving 0.01 and 4 for the Thiele moduli for coke and metal, respectively. The model equation developed in this study is useful to estimate the service life of HDS catalyst.

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Catalytic performance and the surface character of the Ga₂O₃ supported Bi-Mo complex oxides were studied to achieve direct formation of methacrolein from isobutane.
Bi₂Mo₃O₁₂ (α phase) and Bi₂Mo₁O₆ (γ phase) showed higher catalytic activity than Bi₂Mo₂O₉ (β phase) for isobutane partial oxidation. Supporting Ga₂O₃, which is an active catalyst for dehydrogenation of hydrocarbons, onto the oxides, enhanced the catalytic activity.
The optimum amount of supported Ga₂O₃ on Bi₂Mo₃O₁₂ was about 3 wt% for methacrolein formation. In the presence of oxygen, a remarkable amounts of hydrogen over Ga₂O₃ during the isobutane oxidation but no hydrogen was formed over Ga₂O₃⁄Bi₂Mo₃O₁₂. It is confirmed from TPR that Ga₂O₃ and Bi₂Mo₃O₁₂ were not reduced until 550°C but the reduction of Ga₂O₃/Bi₂Mo₃O₁₂ started at 350-380°C. The on-set temperature in TPR of the Bi-Mo complex oxides decreased to 350-380°C from 500°C by the supporting Ga₂O₃ onto the oxides, and the catalysts after TPR measurement are composed of BiO, Bi, and MoO₂ in addition to Bi₂Mo₃O₁₂. These results suggest that the hydrogen spillover took place over supported catalyst.
Ga₂O₃/Bi₂Mo₃O₁₂ catalyst showed higher activity and high selectivity for methacrolein at 450°C. The improvement in the selectivity for methacrolein of the Ga₂O₃/Bi₂Mo₃O₁₂ may be explained as following. Isobutane is adsorbed on the surface of Ga₂O₃ to form hydrogen atom and t-butyl fragment and both formed species migrates to Bi₂Mo₃O₁₂ surface. Migrated hydrogen may modify the Bi₂Mo₃O₁₂ surface property by the reaction with oxide ions, which is active for the deep oxidation resulting in high selectivity for methacrolein.
In the non-aerobic oxidation of isobutane over the Ga₂O₃/Bi₂Mo₃O₁₂ catalyst, the formation rate of CO_x significantly reduced, and methacrolein and isobutene were selectively obtained when the reduction degree of the catalyst was lower than 0.3% at 450°C.

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Acidic properties of three types of (VO)₂P₂O₇ catalysts were investigated by temperature programmed desorption (TPD) using 3, 5- and 2, 6-dimethylpyridine as probes, and the selective oxidation of butane to maleic anhydride (MA) was performed. VPO-org was prepared in organic solvent, VPO-redu was obtained by reduction of VOPO₄·2H₂O, and VPO-aq was prepared in aqueous medium. 3, 5-Dimethylpyridine (3, 5-DMP) is adsorbed on both Brønsted and Lewis acid sites, whereas 2, 6-dimethylpyridine (2, 6-DMP) is selectively adsorbed on Brønsted acid sites due to the steric hindrance of the two methyl groups, so the amounts and strengths of the Brønsted and Lewis acid sites could be determined separately. The (VO)₂P₂O₇ catalysts had four types of acid sites: weak and strong Brønsted acid sites, and weak and strong Lewis acid sites. The acidic properties were greatly dependent on the preparation methods as follows: VPO-org had a larger amount of the strong Brønsted acid sites and these acid sites were relatively weak. VPO-redu had a larger amount of the strong Lewis acid sites and VPO-aq had fewer acid sites. The selectivity to MA at low conversion increased with the amount of strong Lewis acid sites, indicating that the strong Lewis acid sites are important for MA formation. The strong Brønsted acid sites may promote the consecutive oxidation of MA.

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The conventional methods for biomass gasification to hydrogen and synthesis gas are carried out at high temperature. Recently Rh/CeO₂ based catalysts has been shown to be very effective for the catalytic gasification of cellulose at low reaction temperatures. The catalyst performance of Rh/CeO₂/SiO₂ catalysts was investigated using a continuous feed fluidized bed reactor and cellulose as a model compound of biomass. The performance of the Rh/CeO₂/SiO₂ catalysts was very dependent on the loading amount of CeO₂, so the optimum loading was determined. Furthermore, analysis of the product distribution over various catalysts suggests that coke is removed by combustion with oxygen and tar is converted to synthesis gas via the reforming reaction. The low temperature catalytic gasification of cellulose requires high catalyst activity for combustion and reforming, and our optimized catalyst showed adequate activities for both reactions.

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In Japan, the recycling rate of waste plastics by conversion into oil is less than 1%, suggesting inadequate performance of available liquefaction plants in view of the current economic and political demands. The capacities and costs of plants developed between 1990-2000 were investigated. The reactors of most small plants are the batch type. Only a few flow type reactors are currently in operation. The capacity of each plant for converting waste plastics to oil is generally less than 1.5 ton/day. The treatment capacity of tank reactors is less than 1.0 ton/day. The plastic treatment cost of each plant and the plastic treatment capacity were calculated to evaluate commercial operation producing fuel oil from waste plastics. The estimates showed that operation by a flow reactor process would run at a profit of (+)¥23.5/kg for a plant with a capacity of 2.4 ton/day (construction cost 50 million yen). In contrast, operation by a batch reactor process would result in a loss of (-)¥38.1/kg and (-)¥7.8/kg in the cases of plant capacity of 1.0 ton/day (construction cost 70 million yen) and 1.5 ton/day (construction cost 80 million yen), respectively. A small profit would result from running a batch reactor at 2.0 ton/day. These estimates of each reactor process indicate the economic superiority of the flow reactor process, which has a larger treatment capacity and a higher yield of fuel oil with the minimum formation of carbon.

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TiO₂-SiO₂ supports were prepared by impregnation of Ti(OCH(CH₃)₂)₄ on SiO₂. These supports were characterized by use of BET surface area and XRD. Pd catalysts supported on TiO₂-SiO₂ binary oxides showed the higher catalytic activity for naphthalene hydrogenation as compared with that supported on SiO₂ or TiO₂, and the optimum TiO₂ content was 20%.

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