The present disclosure relates to tungsten complexes, catalyst systems including tungsten complexes, and polymerization processes to produce polycycloolefin polymers such as polycyclopentene polymers and polycyclooctene polymers.

A catalyst system including the product of the combination of an unbridged Group 4 metallocene compound and a 2,6-bis(imino)pyridyl iron complex is provided. A process for the polymerization of monomers (such as olefin monomers) and a polymer produced therefrom are also provided.

Provided are a chromium catalyst precursor, an ethylene oligomerization catalyst including the same, and a method of preparing an ethylene oligomer using the same. More particularly, a chromium catalyst precursor which may oligomerize ethylene with high activity and high selectivity in spite of not using methylaluminoxane (MAO) or modified-methylaluminoxane (MMAO), an oligomerization catalyst including the same, and a method of preparing an ethylene oligomer using the same are provided.

Novel compositions and systems for closure of wounds are disclosed. The compositions provide devices of improved flexibility and elasticity and are readily applied to wound sites or over wound closure devices. The present invention is also directed to a novel platinum catalyst for use in such compositions. The catalyst provides for rapid curing on topical surfaces such as skin and bonds to such surfaces in about 2-5 minutes.

Nanoparticles that can be used as hydrosilylation and dehydrogenative silylation catalysts. The nanoparticles have at least one transition metal with an oxidation state of 0, chosen from the metals of columns 8, 9 and 10 of the periodic table, and at least one carbonyl ligand, preferably a silicide.

Provided is a propylene oxide production apparatus including a switching mechanism that is capable of switching a state of each reactor between an operating state where reaction raw materials are supplied and an epoxidation reaction is performed and a non-operating state where the supply of the reaction raw materials is shut off. The propylene oxide production apparatus is capable of changing a reactor in the non-operating state one by one, and performs switching in such a way that only reactors in the operating state are connected fluidically in series or in parallel, thereby enabling supplying the reaction raw materials to the reactors in the operating state. A sampling mechanism is also provided that samples part of the reaction mixture from each discharge line that is connected to each reactor.

A composition containing the following components: (a) a hydrosilylation catalyst comprising a metal-ligand complex, and (b) an inhibitor of the catalyst, wherein the inhibitor differs from the ligand of the metal-ligand complex and is represented by formula (I):

X—CHR—CO—Y  (I),

wherein —X represents —NO.sub.2, —S(═O)R, or R.sup.c.sub.2R.sup.aC—CO—; Y represents 2-furyl, —S(═O)R, —CN, —NO.sub.2, or —CR.sup.b.sub.xR.sup.d.sub.3-x; R.sup.a and R.sup.b is independently selected from the group consisting of —O—R, —O—CO—R, —CO—O—R, 2-furyl, —S(═O)R, —CN, —NO.sub.2, —F, —Cl, and —Br; each of R is independently selected from the group consisting of —H, optionally fluorinated C.sub.1-C.sub.8-alkyl, —F, —Cl, and —Br; each of R.sup.c and each of R.sup.d is independently selected from the group consisting of —H, optionally fluorinated C.sub.1-C.sub.8-alkyl, —F, —Cl, and —Br; and x is 0 or 1.

Methods and catalysts for oxidizing ammonia to nitrogen are described. Specifically, diruthenium complexes that spontaneously catalyze this reaction are disclosed. Accordingly, the disclosed methods and catalysts can be used in various electrochemical cell-based energy storage and energy production applications that could form the basis for a potential nitrogen economy.

The alkylation of transition metal coordination catalyst complexes (such as metallocenes and/or post-metallocenes) in non-polar solvents with high conversion to the dialkylated transition metal coordination catalyst complex may be accomplished by reacting (a) a transition metal coordination catalyst complex comprising a transition metal linked to at least one an anionic donor ligand and at least one leaving group having a non-carbon atom directly linked to the transition metal, (b) an aluminum alkyl, and (c) a fluoride salt at 0° C. to 85° C. in a non-polar solvent to yield an alkylated transition metal coordination catalyst complex.

Cyclopentadienyl platinum complexes bearing ethylenic unsaturation are efficient photocatalysts for hydrosilylation of compounds containing aliphatic carbon-carbon multiple bonds, while exhibiting extended dark time, and are particularly useful in addition-curable organopolysiloxane compositions.