A nanofibrous catalyst for in the electrolyzer and methods of making the catalyst. The catalysts are composed of highly porous transition metal carbonitrides, metal oxides or perovskites derived from the metal-organic frameworks and integrated into a 3D porous nano-network electrode architecture. The catalysts are low-cost, highly active toward OER, with excellent conductivity yet resistant to the oxidation under high potential operable under both acidic and alkaline environments.

The invention concerns a process for the preparation of a catalyst based on tungsten intended for hydrotreatment or hydrocracking processes. The invention concerns a process for the preparation of a catalyst for carrying out hydrogenation reactions in hydrotreatment and hydrocracking processes. Said catalyst is prepared from at least one mononuclear precursor compound based on tungsten (W), in its monomeric or dimeric form, having at least one WO or WOR bond or at least one WS or WSR bond where [RC.sub.xH.sub.y where x1 and (x1)y(2x+1) or RSi(OR).sub.3 or RSi(R).sub.3 where RC.sub.xH.sub.y where x1 and (x1)y(2x+1)], optionally at least one Mo precursor and optionally at least one promoter element from group VIII. Said precursors are deposited onto an oxide support which is suitable for the process in which it is used, said catalyst advantageously being sulphurized before being deployed in said process.

The invention relates to an N-heterocyclic carbene complex of general formulas I to IV (I) (II) (III) (IV), according to which A1 stands for NR2 or PR2, A2 stands for CR2 R2, NR2, PR2, 0 or S, A3 stands for N or P, and C stands for a carbene carbon atom, ring B is an unsubstituted or a mono or poly-substituted 5 to 7-membered ring, substituents R2 and R2 stand, inter alia, for a linear or branched C1-Cw-alkyl group and, if N and N each stand for NR2 or PR2, are the same or different, M in formulas I, II, III or IV stands for Cr, Mo or W, X 1 or X2 in formulas I to IV are the same or different and represent, inter alia, C1-C1s carboxylates and C1-C1s-alkoxides, Y is inter alia oxygen or sulphur, Z is inter alia a linear or branched C1-Cw-alkylenoxy group, and R 1 and R1 in formulas I to IV are, inter alia, an aliphatic or aromatic group. These compounds are particularly suitable for use as catalysts for olefin metathesis reactions and have the advantage, compared to known Schrock carbene complexes, of displaying clearly increased tolerance to functional groups such as, in particular, aldehydes, secondary amines, nitriles, carboxylic acids and alcohols.

The disclosure provides Group 6 complexes, which, in some embodiments, are useful for catalyzing olefin metathesis reactions. In some embodiments, the compounds are compounds of the following formula (I) wherein: M is a Group 6 metal atom; X is an oxygen atom, NR.sup.5, NN(R.sup.5)(R.sup.5) or NOR.sup.5, R.sup.5 and R.sup.5 independently being various substituents, such as aryl or heteroaryl, each optionally substituted; n is 0 or 1; R.sup.z is a neutral ligand; R.sup.1 is hydrogen or an organic substituent; R.sup.2 is an aryl or heteroaryl group, each optionally substituted; R.sup.3 is an anionic ligand; and R.sup.4 is an anionic ligand, such as a pyrrolide, a pyrazolide, an imidazolide, an indolide, an azaindolide, or an indazolide, each optionally substituted.

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The invention concerns an alkane metathesis catalyst, its production and use. The catalyst comprises a Group V, VI or VII metal alkyl with the metal in its highest oxidation state, preferably Ta or W, and the alkyl of C1-C4, preferably together with alkylidene and/or alkylidyne ligands, in particular -Me, CH2 and CH, on a metal oxide support, preferably silica partially dehydroxylated at 200 or 700 C. Substrates include cycloalkanes, preferably cyclooctane.

Provided is a process for hydrogenolysis of a polymer that includes providing in a reactor the polymer, hydrogen gas and a supported organometallic catalyst. The supported organometallic catalyst formed from an organometallic complex precatalyst and an acidic metal oxide support. The polymer is reacted with the supported organometallic catalyst in the presence of the hydrogen gas at a predetermined temperature in the reactor to produce a reduced polymer product having a weight average molecular weight less than the polymer.

Compositions can include compounds having a formula: Co.sub.yW.sub.1-xMx0.sub.4 (I), wherein M is Mo, V, or Nb; 0.5x0; and 1<y4; and wherein the compound has an X-ray powder diffraction pattern including characteristic diffraction peaks having d-spacing values of about 2.90 , 2.56 , and 1.73 . Methods can include making a bulk catalyst composition including (i) combining tungstic acid and cobalt carbonate and (ii) reacting the tungstic acid and cobalt carbonate to form a catalyst composition, wherein the cobalt carbonate has an X-ray powder diffraction pattern including characteristic diffraction peaks having d-spacing values of about 10.03 , 5.91 , 4.35 , and 4.21 .

An improved catalyst for cyclic olefin polymerization. The catalyst includes a transition metal carbene having the following structure: M.sup.v(OR).sub.c*mX.sub.(v-c*m-2)C(R*).sub.2 wherein M.sup.v is a Group 5 transition metal having a valence (v) of 5 or a Group 6 transition metal having a valence (v) of 5 or 6; each R is independently a monovalent organic moiety comprising from 8 to 40 atoms selected from Groups 14-17; c is an integer from 1 to 3; m is 1/3, 1/2, 1, 3/2, 2, 3, or 4 and c*mv2; X is a halogen; and each R* is independently H or a C.sub.1 to C.sub.7 alkyl. The catalyst is particularly useful for ring-opening metathesis polymerization (ROMP).