Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

A system for oxidative conversion of a mixed hydrocarbon feed stream to a product stream containing at least one olefin is provided. The system includes a plurality of reactors each capable of oxidatively dehydrogenating at least a portion of a hydrocarbon in the mixed hydrocarbon feed, and each reactor able to operate at different set of reaction conditions from other reactors in the plurality of reactors. All of the reactors use the same oxygen transfer agent to produce at least one olefin. In some embodiments, at least one reactor is optimized to oxidatively couple methane to produce ethylene, while other reactors are optimized to oxidatively dehydrogenate ethane to ethylene or to oxidatively dehydrogenate propane to ethylene and/or propylene. All of the reactors feed into a single regeneration unit for the oxygen transfer agent. A method of oxidatively converting the mixed hydrocarbon feed to an olefin is also provided.

A reactor system for dehydrogenation of alkanes in a given temperature range upon bringing a reactant stream including alkanes into contact with a catalytic mixture. The reactor system includes a reactor unit arranged to accommodate the catalytic mixture, where the catalytic mixture includes catalyst particles and a ferromagnetic material. The catalyst particles are arranged to catalyze the dehydrogenation of alkanes. The ferromagnetic material is ferromagnetic at least at temperatures up to an upper limit of the given temperature range. The reactor system moreover includes an induction coil arranged to be powered by a power source supplying alternating current and being positioned so as to generate an alternating magnetic field within the reactor unit upon energization by the power source, whereby the catalytic mixture is heated to a temperature within the temperature range by means of the alternating magnetic field. Also, a catalytic mixture and a method of dehydrogenating alkanes.

This disclosure relates to catalyst compositions including gallium and a zirconium-based mixed oxide support, to methods for making such catalysts, and to methods for dehydrogenating hydrocarbons with such catalysts. For example, in one embodiment, a catalyst composition includes a mixed oxide support comprising at least about 50 wt. % of zirconium oxide, the mixed oxide support being present in the composition in an amount within the range of about 40 wt. % to about 99.9 wt. %; and disposed on the support, gallium, present in the composition in an amount within the range of about 0.1 wt. % to about 30 wt. %, calculated as Ga.sub.2O.sub.3 on a calcined basis.

This disclosure relates to catalyst compositions including gallium and a zirconium-based mixed oxide support, to methods for making such catalysts, and to methods for dehydrogenating hydrocarbons with such catalysts. For example, in one embodiment, a catalyst composition includes a mixed oxide support comprising at least about 50 wt. % of zirconium oxide, the mixed oxide support being present in the composition in an amount within the range of about 40 wt. % to about 99.9 wt. %; and disposed on the support, gallium, present in the composition in an amount within the range of about 0.1 wt. % to about 30 wt. %, calculated as Ga.sub.2O.sub.3 on a calcined basis.

Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

This disclosure relates to a system and method for transitioning vehicle control between autonomous operation and manual operation. The system includes sensors configured to generate output signals conveying information related to the vehicle and its operation. During autonomous vehicle operation, the system gauges the level of responsiveness of a vehicle operator through challenges and corresponding responses. The system determines when to present a challenge to the vehicle operator based on internal and external factors. If necessary, the system will transition from an autonomous operation mode to a manual operation mode.