T. A. Nosova

Synthesis of complex hydroxo salts of magnesium, nickel, cobalt, aluminum, and bismuth and oxide catalysts on their base

Synthesis methods have been developed for the precursors of oxide catalysts that include the combination of magnesium nickel cobalt aluminum hydroxocarbonate, with a layered hydrotalcite-type structure and decavanadate and paramolybdate ions in the anion layers, and bismuth hydroxocarbonate. On the base of these precursors, multicomponent oxide catalysts have been manufactured for the oxidative dehydrogenation (OD) of light alkanes. Some of these catalysts showed high selectivities and high product yields in the conversion of ethane to ethylene.

Tantalum-containing catalysts for oxydehydrogenation of hydrocarbons and alcohols

The first methods are developed for introducing niobium(V) into Mg-Al hydrotalcites used as precursors of oxide catalysts for oxydehydrogenation (OD) of alkanes and alcohols. Samples of niobium(V)-containing oxide catalysts are synthesized. Their catalytic properties are studied in oxydehydrogenation of ethane and ethylbenzene to styrene, oxidation dehydrocyclization of octane into ethylbenzene and styrene, and oxydehydrogenation of sec-butanol to ketone (octane-(2)-one). It is ascertained that ethane transformation into ethylene is highly a selective highly process (92–97%) at low temperatures (450–500°C) in the presence of a niobium-containing catalyst; the catalyst is appreciably efficient in ethylbenzene transformation to styrene and dehydrocyclization of n-octane to ethylbenzene and styrene, and in oxydehydrogenation of secbutanol to octane-(2)-one. All the catalysts studied operate stably in OD reactions; no decrease in their activity or selectivity was detected after 50 h operation.

Chromium, vanadium, molybdenum, tungsten, magnesium, and aluminum hydrotalcite hydroxo salts and oxide catalysts on their base

A method is developed for the synthesis of chromium-containing catalysts for the oxidative dehydrogenation (ODH) of alkanes, comprising the precipitation, from nitrate solutions, of mixtures of isomorphic hydrotalcite-type magnesium aluminum and magnesium chromium hydroxocarbonates and the incorporation of oxovanadate, oxomolybdate, and oxotungstate ions by means of anion exchange and subsequent heat treatment. A series of oxide catalyst samples with progressively more complex compositions were prepared: Mg-Al, V-Mg-Al, V-Mo-Mg-Al, Cr-V-Mg-Al, Cr-V-Mo-Mg-Al, and Cr-V-Mo-W-Mg-Al. The catalytic properties of these complex oxides in the ODH of ethane and propane are improved with progressively complex compositions. Chromium-containing catalysts have higher selectivities and provide higher conversions compared to state-of-the-art iron- and nickel-containing oxides.

Tungsten-containing catalysts for oxidative dehydrogenation of hydrocarbons

Methods for introducing tungsten into the precursors of oxide catalysts for oxidative dehydrogenation (OD) were developed. Tungsten-containing samples of oxide catalysts of various compositions were synthesized and their catalytic properties in OD of ethane were studied. The introduction of tungsten into the catalysts increased the yield of ethylene in all cases. In the series of tungsten-containing catalysts, the ethylene yield increased in the following order of the catalysis: Mg-Al-V-Mo-W-O < Mg-Al-Ni-V-Mo-W-O < Mg-Al-Fe-V-Mo-W < Mg-Al-Cr-V-Mo-W-O.

Magnesium iron aluminum hydroxosalts and oxide catalysts for oxidative dehydrogenation of alkanes and alcohols

Methods are developed for the synthesis of precursors for oxide catalysts containing iron hydroxocarbonate and magnesium aluminum hydroxocarbonate with hydrotalcite-type layered structure and decavanadate and paramolybdate ions in anionic interlayers. These precursors are used to synthesize oxide catalysts for oxidative dehydrogenation of alcohols and alkanes with high selectivity and good yields of the desired product in conversion of ethane to ethylene and alcohols to carbonyl compounds.

Indium-containing catalysts for oxidative dehydrogenation of organic compounds

For the first time, a method was developed for introducing indium into Mg-Al hydrotalcites—precursors of oxide catalysts for oxidative dehydrogenation of alkanes. Samples of oxide catalysts were synthesized that contained indium oxide and also oxides of magnesium, aluminum, chromium, vanadium, molybdenum, and niobium in various combinations. The catalytic properties of the produced catalysts were studied in the oxidative dehydrogenation of ethane, propane, and isobutane. It was established that the introduction of indium into catalysts increases the selectivity and the yields of desired products. New hydroxo salts with a layered structure of the hydrotalcite type were synthesized: [Al1 − nInnMgm(OH)3 + 2m − 1][(NO3) · nH2O] and quaternary magnesium indium chromium aluminum hydroxonitrate of the composition [Al0.5In0.5Cr0.5Mg2.5(OH)8.5][(NO3) · nH2O]; these salts were found to be isostructural. The obtained compounds were studied as catalyst precursors.

Copper-containing catalysts for the oxidative dehydrogenation of organic compounds

A method of doping magnesium aluminum hydrotalcites, which are precursors for oxidative dehydrogenation oxide catalysts of various compositions, with copper(II) was developed, and copper(II)-containing oxide catalyst samples were synthesized. The catalytic properties of these catalysts were studied in the oxidative dehydrogenation of ethane, propane, and hexane. The conversion of ethane into ethylene on the copper-containing catalysts was established to proceed with high selectivities (90–97%) and at low temperatures (400–450°C).

Samarium-containing catalysts of oxidative dehydrogenation of alkanes

A method was developed for introducing samarium into Mg-Al hydrotalcites, which are precursors of oxide catalysts for oxidative dehydrogenation of alkanes. Samples of oxide catalysts were synthesized that contained samarium oxide and also various combinations of magnesium, aluminum, chromium, vanadium, molybdenum, and niobium oxides. The catalytic properties of the produced catalysts were studied in the oxidative dehydrogenation of ethane, propane, and isobutane. Addition of samarium to some of the multicenter catalysts under study was found to increase the selectivity and the yield of target products.

Europium oxide containing catalysts for oxidative dehydrogenation of alkanes

A method is developed to incorporate europium into Mg–Al hydrotalcites, which are precursors for oxide catalysts of oxidative dehydrogenation (ODH) of alkanes; samples of oxide catalysts are prepared, where europium oxide and gallium, magnesium, aluminum, chromium, vanadium, molybdenum, and niobium oxides are contained in various combinations. The catalytic properties of these catalysts in the reactions of ethane, propane, and butane ODH are studied. The incorporation of europium into some of our studied multicomponent catalysts enhances the reaction selectivity and increases yields of desired products.