The invention relates to a method for producing an isocyanate, wherein a carbamate or thiolcarbomate is converted, in the presence of a catalyst, with separation of an alcohol or thioalcohol, at a temperature of at least 150 C., to the corresponding isocyanate, wherein a compound of the general formula (X)(Y)(ZH) is used as a catalyst, in particular characterized in that the compound has both a proton donor function and a proton acceptor function. In the catalysts according to the invention, a separable proton is bound to a heteroatom, which is more electronegative than carbon. Said heteroatom is either identical to Z or a component thereof. In the catalysts according to the invention, there is additionally a proton acceptor function which is either identical to X or a component thereof. According to the invention, the proton donator and proton acceptor function are connected to each other by the bridge Y.

The invention relates to a method for producing an isocyanate, wherein a carbamate or thiolcarbomate is converted, in the presence of a catalyst, with separation of an alcohol or thioalcohol, at a temperature of at least 150 C., to the corresponding isocyanate, wherein a compound of the general formula (X)(Y)(ZH) is used as a catalyst, in particular characterized in that the compound has both a proton donor function and a proton acceptor function. In the catalysts according to the invention, a separable proton is bound to a heteroatom, which is more electronegative than carbon. Said heteroatom is either identical to Z or a component thereof. In the catalysts according to the invention, there is additionally a proton acceptor function which is either identical to X or a component thereof. According to the invention, the proton donator and proton acceptor function are connected to each other by the bridge Y.

The invention relates to a method for producing an isocyanate, wherein a carbamate or thiolcarbomate is converted, in the presence of a catalyst, with separation of an alcohol or thioalcohol, at a temperature of at least 150 C., to the corresponding isocyanate, wherein a compound of the general formula (X)(Y)(ZH) is used as a catalyst, in particular characterized in that the compound has both a proton donor function and a proton acceptor function. In the catalysts according to the invention, a separable proton is bound to a heteroatom, which is more electronegative than carbon. Said heteroatom is either identical to Z or a component thereof. In the catalysts according to the invention, there is additionally a proton acceptor function which is either identical to X or a component thereof. According to the invention, the proton donator and proton acceptor function are connected to each other by the bridge Y.

The present invention relates to a new process for preparing polyisocyanates containing isocyanurate groups and being flocculation-stable in solvents from (cyclo)aliphatic diisocyanates.

An isocyanate production method is characterized by having: a carbamation step in which a carbonic acid ester, an inorganic acid salt of an amino acid derivative, and a basic compound are reacted to obtain a reaction mixture containing a carbamic acid ester derived from the carbonic acid ester, a hydroxy compound derived from the carbonic acid ester, and the carbonic acid ester; and a thermal decomposition step in which the carbamic acid ester is subjected to a thermal decomposition reaction to obtain an isocyanate.

An isocyanate production method according to the present invention is a method in which an isocyanate is produced by subjecting a carbamate to thermal decomposition, and includes: a step of preparing a mixture liquid containing the carbamate, an inactive solvent and a polyisocyanate compound; a step of conducting a thermal decomposition reaction of the carbamate by continuously introducing the mixture liquid into a thermal decomposition reactor; a step of collecting a low-boiling decomposition product by continuously extracting the low-boiling decomposition product in a gaseous state from the reactor, the low-boiling decomposition product having a boiling point lower than the polyisocyanate compound; and a step of collecting a high-boiling component by continuously extracting, from the reactor, a liquid phase component which is not collected in a gaseous state at the step of collecting the low-boiling decomposition product.

An isocyanate production method according to the present invention is a method in which an isocyanate is produced by subjecting a carbamate to thermal decomposition, and includes: a step of preparing a mixture liquid containing the carbamate, an inactive solvent and a polyisocyanate compound; a step of conducting a thermal decomposition reaction of the carbamate by continuously introducing the mixture liquid into a thermal decomposition reactor; a step of collecting a low-boiling decomposition product by continuously extracting the low-boiling decomposition product in a gaseous state from the reactor, the low-boiling decomposition product having a boiling point lower than the polyisocyanate compound; and a step of collecting a high-boiling component by continuously extracting, from the reactor, a liquid phase component which is not collected in a gaseous state at the step of collecting the low-boiling decomposition product.

An isocyanate composition according to the present invention contains an isocyanate compound of formula (1) and/or (2) (wherein R.sup.1 represents a hydrogen or a monovalent organic group, and R.sup.2 represents a monovalent organic group), and, relative to the total mass of the isocyanate compound in the composition, 1.0 ppm by mass to 10% by mass of a compound of formula (3): R.sup.13(COOR.sup.14)a (wherein R.sup.13 represents an organic group with a valence of a, R.sup.14 represents a monovalent organic group, and a represents an integer of 1 or 2), which is different from the isocyanate compound, and/or, 1.0 ppm by mass to 10% by mass of a compound having an UV absorption in an area of decamer or higher isocyanates in a measurement spectrum of gel permeation chromatography.

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Materials, methods, and systems for biorthogonal ligation of hydrogel labels to crosslinked-natural polymer hydrogels are provided. A heterobifunctional linker includes a peptide-reactive activated functional group on the heterobifunctional linker, including an activated amine-reactive functional group, an activated thiol-reactive functional group and being reactive with a hydrogel comprising a crosslinked natural polymer. The heterobifunctional linker also includes a photocaged reactive group including a photocaged hydroxylamine, a photocaged alkoxyamine, a photocaged hydrazide, a photocaged amine, a photocaged tetrazine, or a photocaged alkyne-containing moiety. The peptide-reactive activated functional group does not include an azide.

Provided are monomers useful for dental materials that include a compound in which a core and a specific terminal group are bonded to each other directly or via a linking group, wherein the core is a C.sub.1-200 polyvalent organic group having a valence of not less than 3 containing an oxygen atom or a nitrogen atom in which an atom bonded to the terminal group or the linking group is the oxygen atom or the nitrogen atom; the terminal group is a specific (meth)acryloyl group-containing group, a (meth)acryloyl group, a C.sub.1-20 hydrocarbon group or a hydrogen atom, and the terminal group needs to meet specific requirements; and the linking group is a specific divalent group, and when the compound contains a plurality of linking groups, the linking groups may be the same as or different from each other. Compositions, dental materials and kits are also provided.